Fish Population & Control

Recreational fishing is a big business. With more than 46 million anglers in the U.S., fishing can put a lot of pressure on the fish species as well as the environment in which they live. Managing fish populations is a way we can protect and sustain the fishery resources we have today. This management involves habitat oversight, research, stocking and state regulations, and is funded through the Sport Fish Restoration Program.

Fisheries Managers and Biologists

State fish and wildlife agencies employ fisheries managers and biologists to help care for the wildlife and wild places within their states. Fishery biologists are scientists who manage fish populations. To create effective fish management plans, they need as much information about a fishery as possible. They try to learn the needs of anglers and the condition of the specific fish species.

Biologists also need to know how many fish are being caught. They sometimes do this by surveying anglers after a day of fishing. Sometimes, biologists study fish by collecting them with nets or in other ways. Biologists also mark fish with special tags or by clipping one or more of their fins. When marked fish are collected later, the biologists learn how fast fish are growing, how many are caught and how far they have traveled.

After studying this information, biologists devise fish management plans and fishing laws that combine best ways to produce more and better fishing for anglers while still conserving resources.

Managing Fish Habitats

There are many ways to protect habitats for fish. As you have likely learned, fish require the right water temperature, oxygen level, food source and cover. For example, if you stocked a trout in warm water, it would not survive very long. Likewise, if you put pike in a lake without vegetation, it wouldn’t do well either.

Managing the vegetation in a body of water can have a big impact on the fish populations. Aquatic plants provide oxygen, attract food and offer protection for fish in most waters. However, too many plants are harmful and can “choke” a lake. Unfortunately, aquatic plants are hard to control. Cutting, poisoning, uprooting excess plant growth and introducing fish that eat vegetation have all been tried to manage weed growth. One of the best controls is limiting the plant food that enters the water in the form of sewage, fertilizers or farm waste.

Building artificial reefs to attract and provide a home for both freshwater and saltwater fish is another way fish management plans can improve some fisheries. Such artificial habitat provides cover, safety and food for fish. Artificial reefs can be as simple as sinking a weighted Christmas tree in a lake or as complex as sinking an old ship offshore in the ocean. Reefs are important because they provide an area for the bottom of the food chain to develop. The algae and plankton that develop there are a source of food for bait fish and game fish.

Because many fish are attracted to them, fishing deep-sea reefs or wrecks is recommended. However, always check with management authorities for fishing regulations before attempting to put something in the water to attract fish. You may need a permit to place structures in a lake or stream.

Hatcheries and Fish Stocking

One very common way fish populations are managed is through fish stocking. Fish stocking uses hatchery-reared fish to enhance existing fisheries and establish new populations within a body of water. Not only does stocking help to regulate fish numbers, it also provides more opportunities for anglers to enjoy a day of fishing.

Stocked fish come from a fish hatchery, a federal or state-run facility that spawns and rears fish in a controlled environment. Some hatcheries also help research and restore endangered species.

Hatcheries raise many kinds of fish for stocking. The most popular freshwater fish that is stocked is trout, but other popular species such as largemouth bass, steelhead, catfish and many more are also stocked. Saltwater species such as striped bass, red drum, salmon and snook are now being raised successfully as well. Many states stock a combination of large and small fish in many lakes and rivers each year.

Fish management plans will include monitoring a stocked lake and attempting to balance the populations of fish species sharing the aquatic environment. Some popular fishing lakes are stocked often, while other may only be stocked on a need basis. Most states only stock public waters, but some states offer opportunities for private ponds and lakes to be stocked as we

Overpopulated Species and Stunting

Certain fish populations, including sunfish, perch and bullheads, would benefit if more people fished for them. Many anglers don’t even know all these fish are out there waiting to be caught. Without enough angling pressure, some species, like panfish may overpopulate a lake or pond, resulting in a lot of very small fish. This phenomenon, called “stunting” can be helped by anglers who take panfish home and discover they’re some of the most delicious fish to eat.